If you've copied skins over from DCS v1.5 into v2.0 alpha (sight unseen), and discovered they don't look so good, here's the secret and the reason, and how to fix them. I looked all over, and couldn't find a good description of what to do... so, i figured it out myself and here's how!~

In V2.0 apparently they introduced a new and more complex/capable shader model. The normal default p51d skins from v1.5 often didn't take advantage of it. (The stock skins that install with the v2 game are OK, cause ED fixed them, but if you're trying to salvage skins from v1.5 over into v2.x In order to correct an existing skin from v1.5 to v2.0 heres what to do.)

- first find the folder/skin you want to correct, this procedure below pertains to all of them>
- look in C:\Program Files\Eagle Dynamics\DCS World 2 OpenAlpha\Bazar\Liveries\P-51D - this is where all the skins are kept... find the folder for the skin you want to fix, eg \MYSKIN\.

(ps - these will impart a very shiny metallic overlay over your entire skin, and clear up the blotchy look - if you want to customize or fine tune the metallic look, or dull it down, thats a lesson for another day, but editing these bitmaps is how you do that).

2.) next edit the C:\Program Files\Eagle Dynamics\DCS World 2 OpenAlpha\Bazar\Liveries\P-51D\description.lua file with a text editor in your skins folder you're trying to correct.
Below is an example of a corrected one.

- you need to add, or correct the lines below in RED, and make sure they are in place in each stanza correctly (as shown below below in the example file). Each line needs to reference the new _RoughMet.dds files you just added to the skins folder. If you're not changing the skin in any other way, then don't change any of the other lines in this file.

PS - if you want to mess around, look into using the \bin\modelviewer.exe in the \game's bin folder, this is a handy tool for use in viewing and manipulating skins without all the overhead of reloading the game.
PPS- Keep in mind, you may not see skin updates until you stop and start the game, DCS loads the skins files necessary often at startup. So close/open after making changes.

With these simple tweaks your lovely P51D v1.5 skins can look great in v2.0 too!